Various audio devices are able to discriminate small differences in loudness (intensity) and pitch (frequency) over a large range of audible sound (for example, between 20 Hz and 20 kHz). These various audio devices can also be used to aquire information about a surrounding environment. The capability to reliably track or detect motion based on these audible sounds, similar to a trained “tracker” as depicted on film and television, is a reality with the current advancements in motion sensor technology. For example, security perimeter sensors can be employed in various locations within a defined area. These perimeter sensors can send and receive radar, video, audio, or seismic signals, and are applicable in many security situations.
Presently, in order to take advantage of particular audio and video signals from these perimeter sensors, specialized monitoring equipment is required. Moreover, this equipment is typically stationed at a remote site some distance away from the area under surveillance. The ability to monitor objects or activity directly within the perimeter is limited, and can result in undesired consequences if one or more sources of the activity are not discovered.